Reuters also quoted parts of the State Department’s letter to Albania’s Foreign Ministry.

The U.S. administration reacted after frequent nationalistic statements of Albanian politicians ahead of the June elections that are “ruffling feathers” in neighboring states that are home to millions of ethnic Albanians.

Last November, the Greek foreign minister boycotted Albanian centenary festivities in Tirana after Albanian PM Sali Berisha hailed a town over the border as "Albanian lands". The president of Macedonia, where a quarter of the population are ethnic Albanians, also stayed away, Reuters pointed out.

The U.S. State Department said Albania's leaders were wading into "potentially dangerous" territory, given the history of ethnic conflicts in the Balkans.

“Such remarks not only promote more inflammatory behavior and distract from this region's priorities, but also potentially incite violence, erode peace and stability, and impact our relationship", the State Department stressed in the memo.

Even more bluntly, it told Albanian politicians to "stay out of the affairs of Serbia", Reuters reports.